The Volkswagen CC front turn signal requires a 12174SV or H21W bulb size, while the rear turn signal uses a PY21W or DE3175 bulb size. The replacement chart covers 2009 through 2013 model years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The H21W is the most frequently specified front turn signal bulb across the Volkswagen CC lineup, covering the 2009-2012 model years. It follows the ECE standard used in Europe and worldwide markets, operates at 12V with a 21W output, uses a single filament, and mounts via a BAY9s base.
The 2013 Volkswagen CC front turn signal departs from the H21W used in prior years, instead specifying the 12174SV, a Philips SilverVision part number denoting a halogen bulb with an enhanced coating that operates at 12V.
Because the 12174SV is a manufacturer-specific part number rather than a universal ECE or ANSI designation, it is not directly interchangeable with the H21W on a specification basis alone, even though both serve the front turn signal position.
The PY21W rear turn signal bulb specified for the 2012-2013 model years follows the ECE standard. It is a single-filament amber bulb rated at 12V and 21W, and it uses a BAU15s bayonet base. The amber coloring is built into the bulb itself rather than produced by a colored lens.
The BAU15s base of the PY21W is offset, meaning the two pins are not positioned symmetrically. This prevents the bulb from being seated in a socket designed for a standard BAY15s base, making cross-substitution physically incompatible without modification.
The DE3175 is specified for the rear turn signal position on the 2009-2011 Volkswagen CC. It follows the ANSI standard common to the US and Canadian markets, is a festoon-type bulb measuring 31mm in length, and makes contact through end caps rather than a bayonet or wedge base.
The rear turn signal specification shifts from the ANSI-standard DE3175 to the ECE-standard PY21W between the 2011 and 2012 model years. These two bulb types use entirely different base configurations and are not interchangeable.
The H21W and PY21W share the same voltage and wattage ratings at 12V and 21W, but their bases differ. The H21W uses a BAY9s base while the PY21W uses a BAU15s base, so they are not physically interchangeable despite the matching electrical ratings.
The DE3175 festoon bulb uses end-cap contacts, a mounting style that is mechanically distinct from both the bayonet bases of the H21W and PY21W and the halogen construction of the 12174SV, placing it in a separate fitment category from all other bulbs listed in these specifications.
Across both the front and rear turn signal positions, the Volkswagen CC draws from two regulatory standards: ECE, represented by the H21W and PY21W, and ANSI, represented by the DE3175. The 12174SV sits outside both frameworks as a proprietary designation.